JP3629749B2 - Electric fusion joint - Google Patents

Electric fusion joint Download PDF

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Publication number
JP3629749B2
JP3629749B2 JP07869095A JP7869095A JP3629749B2 JP 3629749 B2 JP3629749 B2 JP 3629749B2 JP 07869095 A JP07869095 A JP 07869095A JP 7869095 A JP7869095 A JP 7869095A JP 3629749 B2 JP3629749 B2 JP 3629749B2
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Prior art keywords
joint
opening
resin
inner diameter
peripheral surface
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JPH08277987A (en
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崇朗 吉井
英男 関口
孝行 直嶋
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JFE Engineering Corp
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JFE Engineering Corp
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C65/00—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor
    • B29C65/02—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure
    • B29C65/34—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure using heated elements which remain in the joint, e.g. "verlorenes Schweisselement"
    • B29C65/3404—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure using heated elements which remain in the joint, e.g. "verlorenes Schweisselement" characterised by the type of heated elements which remain in the joint
    • B29C65/342—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure using heated elements which remain in the joint, e.g. "verlorenes Schweisselement" characterised by the type of heated elements which remain in the joint comprising at least a single wire, e.g. in the form of a winding
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C65/00—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor
    • B29C65/02—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure
    • B29C65/34—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure using heated elements which remain in the joint, e.g. "verlorenes Schweisselement"
    • B29C65/3468—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure using heated elements which remain in the joint, e.g. "verlorenes Schweisselement" characterised by the means for supplying heat to said heated elements which remain in the join, e.g. special electrical connectors of windings
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C66/00—General aspects of processes or apparatus for joining preformed parts
    • B29C66/01—General aspects dealing with the joint area or with the area to be joined
    • B29C66/05—Particular design of joint configurations
    • B29C66/10—Particular design of joint configurations particular design of the joint cross-sections
    • B29C66/12—Joint cross-sections combining only two joint-segments; Tongue and groove joints; Tenon and mortise joints; Stepped joint cross-sections
    • B29C66/122—Joint cross-sections combining only two joint-segments, i.e. one of the parts to be joined comprising only two joint-segments in the joint cross-section
    • B29C66/1222—Joint cross-sections combining only two joint-segments, i.e. one of the parts to be joined comprising only two joint-segments in the joint cross-section comprising at least a lapped joint-segment
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C66/00—General aspects of processes or apparatus for joining preformed parts
    • B29C66/01—General aspects dealing with the joint area or with the area to be joined
    • B29C66/05—Particular design of joint configurations
    • B29C66/10—Particular design of joint configurations particular design of the joint cross-sections
    • B29C66/12—Joint cross-sections combining only two joint-segments; Tongue and groove joints; Tenon and mortise joints; Stepped joint cross-sections
    • B29C66/122—Joint cross-sections combining only two joint-segments, i.e. one of the parts to be joined comprising only two joint-segments in the joint cross-section
    • B29C66/1224—Joint cross-sections combining only two joint-segments, i.e. one of the parts to be joined comprising only two joint-segments in the joint cross-section comprising at least a butt joint-segment
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C66/00—General aspects of processes or apparatus for joining preformed parts
    • B29C66/01—General aspects dealing with the joint area or with the area to be joined
    • B29C66/32—Measures for keeping the burr form under control; Avoiding burr formation; Shaping the burr
    • B29C66/322—Providing cavities in the joined article to collect the burr
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C66/00—General aspects of processes or apparatus for joining preformed parts
    • B29C66/50—General aspects of joining tubular articles; General aspects of joining long products, i.e. bars or profiled elements; General aspects of joining single elements to tubular articles, hollow articles or bars; General aspects of joining several hollow-preforms to form hollow or tubular articles
    • B29C66/51—Joining tubular articles, profiled elements or bars; Joining single elements to tubular articles, hollow articles or bars; Joining several hollow-preforms to form hollow or tubular articles
    • B29C66/52—Joining tubular articles, bars or profiled elements
    • B29C66/522—Joining tubular articles
    • B29C66/5221—Joining tubular articles for forming coaxial connections, i.e. the tubular articles to be joined forming a zero angle relative to each other
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C66/00—General aspects of processes or apparatus for joining preformed parts
    • B29C66/50—General aspects of joining tubular articles; General aspects of joining long products, i.e. bars or profiled elements; General aspects of joining single elements to tubular articles, hollow articles or bars; General aspects of joining several hollow-preforms to form hollow or tubular articles
    • B29C66/51—Joining tubular articles, profiled elements or bars; Joining single elements to tubular articles, hollow articles or bars; Joining several hollow-preforms to form hollow or tubular articles
    • B29C66/52—Joining tubular articles, bars or profiled elements
    • B29C66/522—Joining tubular articles
    • B29C66/5229—Joining tubular articles involving the use of a socket
    • B29C66/52291—Joining tubular articles involving the use of a socket said socket comprising a stop
    • B29C66/52292—Joining tubular articles involving the use of a socket said socket comprising a stop said stop being internal
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C66/00—General aspects of processes or apparatus for joining preformed parts
    • B29C66/90—Measuring or controlling the joining process
    • B29C66/91—Measuring or controlling the joining process by measuring or controlling the temperature, the heat or the thermal flux
    • B29C66/912—Measuring or controlling the joining process by measuring or controlling the temperature, the heat or the thermal flux by measuring the temperature, the heat or the thermal flux
    • B29C66/9131—Measuring or controlling the joining process by measuring or controlling the temperature, the heat or the thermal flux by measuring the temperature, the heat or the thermal flux by measuring the heat or the thermal flux, i.e. the heat flux
    • B29C66/91311—Measuring or controlling the joining process by measuring or controlling the temperature, the heat or the thermal flux by measuring the temperature, the heat or the thermal flux by measuring the heat or the thermal flux, i.e. the heat flux by measuring the heat generated by Joule heating or induction heating
    • B29C66/91315—Measuring or controlling the joining process by measuring or controlling the temperature, the heat or the thermal flux by measuring the temperature, the heat or the thermal flux by measuring the heat or the thermal flux, i.e. the heat flux by measuring the heat generated by Joule heating or induction heating by measuring the current intensity
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C66/00—General aspects of processes or apparatus for joining preformed parts
    • B29C66/90—Measuring or controlling the joining process
    • B29C66/91—Measuring or controlling the joining process by measuring or controlling the temperature, the heat or the thermal flux
    • B29C66/914—Measuring or controlling the joining process by measuring or controlling the temperature, the heat or the thermal flux by controlling or regulating the temperature, the heat or the thermal flux
    • B29C66/9161—Measuring or controlling the joining process by measuring or controlling the temperature, the heat or the thermal flux by controlling or regulating the temperature, the heat or the thermal flux by controlling or regulating the heat or the thermal flux, i.e. the heat flux
    • B29C66/91651—Measuring or controlling the joining process by measuring or controlling the temperature, the heat or the thermal flux by controlling or regulating the temperature, the heat or the thermal flux by controlling or regulating the heat or the thermal flux, i.e. the heat flux by controlling or regulating the heat generated by Joule heating or induction heating
    • B29C66/91655—Measuring or controlling the joining process by measuring or controlling the temperature, the heat or the thermal flux by controlling or regulating the temperature, the heat or the thermal flux by controlling or regulating the heat or the thermal flux, i.e. the heat flux by controlling or regulating the heat generated by Joule heating or induction heating by controlling or regulating the current intensity
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C65/00—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor
    • B29C65/02—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure
    • B29C65/34—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure using heated elements which remain in the joint, e.g. "verlorenes Schweisselement"
    • B29C65/3472—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure using heated elements which remain in the joint, e.g. "verlorenes Schweisselement" characterised by the composition of the heated elements which remain in the joint
    • B29C65/3476—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure using heated elements which remain in the joint, e.g. "verlorenes Schweisselement" characterised by the composition of the heated elements which remain in the joint being metallic

Description

【０００１】
【産業上の利用分野】
本発明は、熱可塑性樹脂からなるガス管、水道管などを接続するための電気融着継手、特に、その呼び径が７５Ａ以上の大口径の電気融着継手に関する。
【０００２】
【従来の技術】
熱可塑性樹脂でできたガス管、水道管などを接続するための電気融着継手のうち、その呼び径が７５Ａ以上の大口径管用継手では、継手本体の内周面と接続すべき樹脂管の外周面との隙間量が大きくなり、融着時に溶融樹脂が継手開口部から流出することがしばしば起こる。このため樹脂を溶融するために設けてある電熱線も移動し、場合によっては電熱線の短絡という重大なトラブルを招くことがある。
【０００３】
特に、従来の継手のうち、軽量化のため継手の中央部から開口部にかけてテーパー状、あるいは円弧状に肉厚を減じてある継手では、融着時に起こる溶融樹脂の熱膨張によって生じる圧力により継手開口部が拡径し、樹脂流出が起こりやすい。
【０００４】
上記の問題を解決するために、特開昭６２ー１５１６８８号公報、特開昭６４ー７４３８１号公報、特開平４ー１７１３９２号公報、特開平４ー２５８５９４号公報には、継手開口部をワイヤー、形状記憶合金、樹脂テープなどで絞めて、開口部の拡径を押さえ、樹脂の流出を防ぐ方法が提案されている。また、加熱部の溶融樹脂の熱膨張により非加熱部の開口部が縮径するように樹脂の加熱溶融する部分を等肉厚の平坦な構造とし、内圧強度の確保のため継手中央部や開口部の肉厚を厚くした継手も、文献〔Ｓ．ＭｃＰｈｅｒｓｏｎ：ＰＬＡＳＴＩＣＳ ＰＩＰＥＳ ＶＩＩＩ，Ｐｒｏｃｅｅｄｉｎｇｓ ｏｆ Ｃｏｎｆｅｒｅｎｃｅ，ＴＨＥ ＰＬＡＳＴＩＣＳ ＡＮＤ ＲＵＢＢＥＲ ＩＮＳＴＩＴＵＴＥ，１９９２〕に紹介されている。
【０００５】
【発明が解決しようとする課題】
しかしながら、特開昭６２ー１５１６８８号公報、特開昭６４ー７４３８１号公報、特開平４ー１７１３９２号公報、特開平４ー２５８５９４号公報に記載された継手開口部を絞める方法では、電気融着接合の工程が複雑になるとともに、コスト高となる。前記文献に記載された方法では、継手本体の内周面と接続すべき樹脂管の外周面との隙間量が大きくなりすぎると、溶融樹脂の熱膨張により非加熱部の開口部が縮径しても、開口部の内周面は樹脂管の外周面にフィットしなくなり、完全には樹脂流出を防止できなくなる。
【０００６】
また、電気融着継手には、良好な融着性能を確保するため、継手樹脂の温度や圧力を検出するセンサーを継手開口部近傍にある電熱線の上部に設け、電熱線の通電時間を制御できるものもある。前述のようにその呼び径が７５Ａ以上に大きくなると、継手本体の内周面と接続すべき樹脂管の外周面との隙間量が大きくなり、しかも寸法公差があったり、樹脂管をスクレープして（表面を削って）継手に挿入するため、センサー位置におけるこの隙間量を常に一定に保つことが難しくなる。この隙間量が小さすぎると樹脂管側への伝熱量が大きくなって、継手樹脂の特性変化が小さくなりすぎ、また、隙間量が大きすぎると継手側への伝熱量が大きくなって、継手樹脂の特性変化が急激に起こるため、センサーによる安定した通電時間の制御ができなくなり、融着不良を引き起こし易くなる。
【０００７】
本発明はこのような問題を解決するためになされたもので、融着時に継手開口部から溶融樹脂の流出が起こらない電気融着継手、および樹脂流出が起こらずしかもセンサーによる安定した通電制御が可能な通電制御用センサーを備えた電気融着継手を提供することを目的とする。
【０００８】
【課題を解決するための手段】
上記課題は、継手開口部の内径が継手電熱線配設部の内径よりも小さく、かつ継手開口部の肉厚が継手電熱線配設部の肉厚よりも厚いことを特徴とする電気融着継手および前記継手開口部近傍に通電制御用センサーを備えた前記電気融着継手により解決される。
【０００９】
【作用】
融着時、継手電熱線配設部においては溶融樹脂の熱膨張が起こる。呼び径が７５Ａ以上の大口径の電気融着継手の場合、耐圧強度の確保のためその肉厚が厚いので、この膨張した溶融樹脂は、主に管軸方向すなわち開口部に向かって流れ出す。このとき開口部の内径を電熱線配設部の内径より小さくすれば、開口部の内周面と接続すべき樹脂管の外周面との隙間量を小さくでき、かつ開口部の肉厚が厚くなるのでその剛性も高められ開口部の拡径を起こり難くできるので、樹脂流出を防止できる。
【００１０】
通電制御用センサーを備えた電気融着継手において、開口部の内径を電熱線配設部の内径より小さくし、接続すべき樹脂管を、その外周面を前記開口部の内周面に接触させながら継手に挿入すれば、開口部近傍に設けらたセンサー位置において、継手の内周面と樹脂管の外周面との隙間量をより確実に一定にすることができるので、センサーによる安定した通電制御が行える。
【００１１】
開口部の内径を電熱線配設部の内径よりどれくらい小さくするかは、継手を構成する樹脂の種類や継手の形状、呼び径、肉厚あるいはセンサー位置やセンサーの種類などにより、その最適値が異なるので、それぞれに適した値を予め求めておく必要がある。なお、開口部の内径は、樹脂管の継手への挿入性を悪化させるほど小さく（樹脂管の最大外径より小さく）はできない。
【００１２】
【実施例】
（実施例１）
図１に、本発明の１実施例である電気融着継手の管軸に対し直角方向から見た断面形状図を示す。図で、１は継手本体、２は樹脂管、３は継手開口部、４は継手電熱線配設部、５は電熱線、６はストッパー、７は継手中央部である。なお、以下の図においては、図１と同一の部位には同一の符号を付して、説明を省略する。
【００１３】
継手本体１に接続すべき樹脂管２を、その先端がストッパー６にあたるまで挿入するとき、継手開口部３の内径を継手電熱線配設部４の内径より小さくすると、継手開口部３においては、継手開口部３の内周面と樹脂管２の外周面との隙間量が小さくなり、しかも継手開口部３の肉厚が厚くなるのでその剛性を高められ継手開口部３の拡径を起こり難くできるので、樹脂流出を防止できる。
【００１４】
図２に、本発明の１実施例である電気融着継手の管軸に対し直角方向から見た断面形状図を示す。この電気融着継手は、図１の電気融着継手の軽量化のために、継手中央部７から継手開口部３にかけて継手の肉厚を減じたものである。この場合も、図１の電気融着継手の場合と同様な原理で樹脂流出を防止できる。
【００１５】
図３に、本発明の１実施例である電気融着継手の管軸に対し直角方向から見た断面形状図を示す。この電気融着継手は、図１の電気融着継手において継手開口部３の内径を継手電熱線配設部４の内径より小さくするにあたり、継手電熱線配設部４から継手開口部３にかけて除々に小さくしたものである。こうすることにより、融着時の樹脂流出を防止できるばかりか、射出成形後の中子の取り出しがより容易に行える。
【００１６】
図４に、本発明の１実施例である電気融着継手の管軸に対し直角方向から見た断面形状図を示す。この電気融着継手は、図３の電気融着継手において継手中央部７の内径も、継手開口部３の内径と同程度に小さくしたものである。こうすることにより、図３の電気融着継手よりもさらに安定して継手本体１の内周面と樹脂管２の外周面との隙間量を調整できる。
【００１７】
（実施例２）
図５に、本発明の１実施例である通電制御用センサーを備えた電気融着継手の管軸に対し直角方向から見た断面形状図を示す。図で、８は通電制御用センサー、９は通電ターミナルである。この電気融着継手は、図１の電気融着継手において継手中央部７の内径も、継手開口部３の内径と同程度に小さくしてあり、かつ継手開口部３近傍にある電熱線５の上部に通電制御用センサー８を設けたものである。継手開口部３の内径を電熱線配設部４の内径より小さくしてあるので、樹脂流出を防止できるばかりか、通電制御用センサー８の位置において継手本体１の内周面と樹脂管２の外周面との隙間量を一定にできるので通電ターミナル９を介した通電条件を安定して制御できる。さらに、継手中央部７の内径も、継手開口部３の内径と同程度に小さくしてあるので、通電制御用センサー８の位置における継手本体１の内周面と樹脂管２の外周面との隙間量をより確実に一定にでき、より安定した通電制御が可能となる。
【００１８】
【発明の効果】
本発明は以上説明したように構成されているので、融着時に継手開口部から溶融樹脂の流出が起こらない電気融着継手、および樹脂流出が起こらずしかもセンサーによる安定した通電制御が可能な通電制御用センサーを備えた電気融着継手を提供することができる。
【図面の簡単な説明】
【図１】本発明の１実施例である電気融着継手の管軸に対し直角方向から見た断面形状図である。
【図２】本発明の１実施例である電気融着継手の管軸に対し直角方向から見た断面形状図である。
【図３】本発明の１実施例である電気融着継手の管軸に対し直角方向から見た断面形状図である。
【図４】本発明の１実施例である電気融着継手の管軸に対し直角方向から見た断面形状図である。
【図５】本発明の１実施例である通電制御用センサーを備えた電気融着継手の管軸に対し直角方向から見た断面形状図である。
【符号の説明】
１ 継手本体
３ 継手開口部
４ 継手電熱線配線部
８ 通電制御用センサー[0001]
[Industrial application fields]
The present invention relates to an electric fusion joint for connecting a gas pipe made of a thermoplastic resin, a water pipe, and the like, and particularly to an electric fusion joint having a nominal diameter of 75 A or more.
[0002]
[Prior art]
Among electric fusion joints for connecting gas pipes, water pipes, etc. made of thermoplastic resin, in joints for large diameter pipes with a nominal diameter of 75A or more, the resin pipes to be connected to the inner peripheral surface of the joint body The amount of gap with the outer peripheral surface is increased, and the molten resin often flows out of the joint opening during fusion. For this reason, the heating wire provided for melting the resin also moves, and in some cases, a serious trouble of short-circuiting the heating wire may be caused.
[0003]
In particular, among conventional joints, the joint is reduced in thickness by taper or arc shape from the center to the opening of the joint for weight reduction. The diameter of the opening is increased and resin outflow is likely to occur.
[0004]
In order to solve the above problems, JP-A-62-151688, JP-A-64-74381, JP-A-4-171392, and JP-A-4-258594 disclose a joint opening portion as a wire. In addition, a method has been proposed in which the shape memory alloy, resin tape, or the like is used to restrict the diameter of the opening to prevent the resin from flowing out. In addition, the heat-melting part of the resin is made to have a flat and uniform structure so that the opening of the non-heating part shrinks due to the thermal expansion of the molten resin in the heating part. A joint with a thickened part is also described in the literature [S. McPherson: PLASTICS PIPES VIII, Proceedings of Conference, THE PLASTICS AND RUBER INSTITUTE, 1992].
[0005]
[Problems to be solved by the invention]
However, in the method for narrowing the joint opening described in JP-A-62-151688, JP-A-64-74381, JP-A-4-171392, JP-A-4-258594, The joining process becomes complicated and the cost increases. In the method described in the above document, if the gap between the inner peripheral surface of the joint body and the outer peripheral surface of the resin pipe to be connected becomes too large, the opening of the non-heated portion is reduced in diameter due to the thermal expansion of the molten resin. However, the inner peripheral surface of the opening does not fit the outer peripheral surface of the resin tube, and the resin outflow cannot be completely prevented.
[0006]
In addition, in order to ensure good fusion performance, an electric fusion joint is provided with a sensor that detects the temperature and pressure of the joint resin at the top of the heating wire near the joint opening to control the energization time of the heating wire. Some can be done. As described above, when the nominal diameter is increased to 75A or more, the gap amount between the inner peripheral surface of the joint body and the outer peripheral surface of the resin pipe to be connected increases, and there is a dimensional tolerance, or the resin pipe is scraped. Since it is inserted into the joint (shaving the surface), it becomes difficult to always keep this gap amount at the sensor position constant. If this gap amount is too small, the amount of heat transfer to the resin tube side will increase, and the characteristic change of the joint resin will be too small.If the gap amount is too large, the amount of heat transfer to the joint side will increase, and the joint resin will Since the characteristic change occurs rapidly, it becomes impossible to control the energization time stably by the sensor, and it becomes easy to cause poor fusion.
[0007]
The present invention has been made to solve such a problem, and an electric fusion joint in which molten resin does not flow out of the joint opening during fusion, and stable energization control by the sensor without causing resin outflow. An object of the present invention is to provide an electric fusion joint including a sensor for controlling energization.
[0008]
[Means for Solving the Problems]
An object of the present invention is to provide an electric welding characterized in that the inner diameter of the joint opening is smaller than the inner diameter of the joint heating wire arrangement portion , and the thickness of the joint opening is thicker than the thickness of the joint heating wire arrangement portion. The problem is solved by the joint and the electrofusion joint provided with an energization control sensor in the vicinity of the joint opening .
[0009]
[Action]
At the time of fusion, thermal expansion of the molten resin occurs in the joint heating wire arrangement portion. In the case of a large-diameter electrofusion joint having a nominal diameter of 75 A or more, the wall thickness is large in order to ensure the pressure strength, so that the expanded molten resin flows mainly toward the tube axis direction, that is, toward the opening. At this time, if the inner diameter of the opening is made smaller than the inner diameter of the heating wire arrangement part, the gap between the inner peripheral surface of the opening and the outer peripheral surface of the resin pipe to be connected can be reduced, and the thickness of the opening is increased. As a result, the rigidity is increased and the diameter of the opening can hardly be increased, so that the resin can be prevented from flowing out.
[0010]
In an electrofusion joint including an energization control sensor, the inner diameter of the opening is made smaller than the inner diameter of the heating wire, and the resin pipe to be connected is brought into contact with the inner peripheral surface of the opening. However, if it is inserted into the joint, the gap between the inner peripheral surface of the joint and the outer peripheral surface of the resin pipe can be more reliably made constant at the sensor position provided near the opening. Control is possible.
[0011]
The optimal value for how much the inner diameter of the opening should be smaller than the inner diameter of the heating wire arrangement depends on the type of resin making up the joint, the shape of the joint, nominal diameter, thickness, sensor position, sensor type, etc. Since they are different, it is necessary to obtain a value suitable for each. Note that the inner diameter of the opening cannot be so small as to deteriorate the insertion property of the resin pipe into the joint (smaller than the maximum outer diameter of the resin pipe).
[0012]
【Example】
(Example 1)
FIG. 1 is a cross-sectional view of an electrofusion joint according to an embodiment of the present invention viewed from a direction perpendicular to the tube axis. In the figure, 1 is a joint body, 2 is a resin tube, 3 is a joint opening, 4 is a joint heating wire arrangement portion, 5 is a heating wire, 6 is a stopper, and 7 is a joint central portion. In the following drawings, the same parts as those in FIG.
[0013]
When the resin pipe 2 to be connected to the joint body 1 is inserted until its tip hits the stopper 6, if the inner diameter of the joint opening 3 is made smaller than the inner diameter of the joint heating wire arrangement part 4, The gap between the inner peripheral surface of the joint opening 3 and the outer peripheral surface of the resin pipe 2 is reduced, and the thickness of the joint opening 3 is increased, so that the rigidity is increased and the diameter of the joint opening 3 is less likely to increase. As a result, resin outflow can be prevented.
[0014]
FIG. 2 shows a cross-sectional shape of the electrofusion joint according to one embodiment of the present invention viewed from a direction perpendicular to the tube axis. This electric fusion joint is obtained by reducing the thickness of the joint from the joint central portion 7 to the joint opening 3 in order to reduce the weight of the electric fusion joint of FIG. Also in this case, resin outflow can be prevented by the same principle as in the case of the electric fusion joint of FIG.
[0015]
FIG. 3 shows a cross-sectional shape of the electrofusion joint according to one embodiment of the present invention as viewed from the direction perpendicular to the tube axis. In order to make the inner diameter of the joint opening 3 smaller than the inner diameter of the joint heating wire arrangement portion 4 in the electric fusion joint of FIG. 1, the electric fusion joint gradually increases from the joint heating wire arrangement portion 4 to the joint opening portion 3. It is a small one. By doing so, not only can the resin flow out during fusion, but also the core after injection molding can be taken out more easily.
[0016]
FIG. 4 shows a cross-sectional shape of the electrofusion joint according to one embodiment of the present invention viewed from a direction perpendicular to the tube axis. In this electrofusion joint, the inner diameter of the joint central portion 7 in the electrofusion joint of FIG. 3 is also made as small as the inner diameter of the joint opening 3. By doing so, the gap amount between the inner peripheral surface of the joint body 1 and the outer peripheral surface of the resin tube 2 can be adjusted more stably than the electrofusion joint of FIG.
[0017]
(Example 2)
FIG. 5 shows a cross-sectional shape of an electrofusion joint provided with a current-carrying control sensor according to an embodiment of the present invention as viewed from the direction perpendicular to the tube axis. In the figure, 8 is an energization control sensor, and 9 is an energization terminal. In the electric fusion joint, the inner diameter of the joint central portion 7 in the electric fusion joint of FIG. 1 is made as small as the inner diameter of the joint opening 3, and the heating wire 5 in the vicinity of the joint opening 3 is An energization control sensor 8 is provided at the top. Since the inner diameter of the joint opening 3 is made smaller than the inner diameter of the heating wire disposing part 4, not only can resin be prevented from flowing out, but also the inner peripheral surface of the joint body 1 and the resin pipe 2 at the position of the energization control sensor 8. Since the gap amount with the outer peripheral surface can be made constant, the energization condition via the energization terminal 9 can be controlled stably. Furthermore, since the inner diameter of the joint central portion 7 is also made as small as the inner diameter of the joint opening 3, the inner peripheral surface of the joint main body 1 and the outer peripheral surface of the resin pipe 2 at the position of the energization control sensor 8. The gap amount can be made constant more reliably, and more stable energization control becomes possible.
[0018]
【The invention's effect】
Since the present invention is configured as described above, an electric fusion joint in which molten resin does not flow out of the joint opening at the time of fusion, and energization that does not cause resin outflow and can be stably controlled by the sensor. An electric fusion joint provided with a control sensor can be provided.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of an electrofusion joint according to an embodiment of the present invention viewed from a direction perpendicular to a tube axis.
FIG. 2 is a cross-sectional view of the electrofusion joint according to one embodiment of the present invention as viewed from a direction perpendicular to the tube axis.
FIG. 3 is a cross-sectional view of the electrofusion joint according to one embodiment of the present invention as viewed from a direction perpendicular to the tube axis.
FIG. 4 is a cross-sectional view of the electrofusion joint according to one embodiment of the present invention viewed from a direction perpendicular to the tube axis.
FIG. 5 is a cross-sectional shape view of the electrofusion joint provided with a current-carrying control sensor according to one embodiment of the present invention as viewed from the direction perpendicular to the tube axis.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Joint body 3 Joint opening part 4 Joint heating wire wiring part 8 Power supply control sensor

Claims (2)

継手開口部の内径が継手電熱線配設部の内径よりも小さく、かつ継手開口部の肉厚が継手電熱線配設部の肉厚よりも厚いことを特徴とする電気融着継手。An electrofusion joint characterized in that an inner diameter of a joint opening is smaller than an inner diameter of a joint heating wire arrangement portion , and a thickness of the joint opening is thicker than a thickness of the joint heating wire arrangement portion . 前記継手開口部近傍に通電制御用センサーを備えたことを特徴とする請求項１に記載の電気融着継手。The electrofusion joint according to claim 1, further comprising an energization control sensor in the vicinity of the joint opening .
JP07869095A 1995-04-04 1995-04-04 Electric fusion joint Expired - Lifetime JP3629749B2 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP07869095A JP3629749B2 (en) 1995-04-04 1995-04-04 Electric fusion joint

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP07869095A JP3629749B2 (en) 1995-04-04 1995-04-04 Electric fusion joint

Publications (2)

Publication Number Publication Date
JPH08277987A JPH08277987A (en) 1996-10-22
JP3629749B2 true JP3629749B2 (en) 2005-03-16

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Publication number Priority date Publication date Assignee Title
JP5173571B2 (en) * 2008-05-09 2013-04-03 大阪瓦斯株式会社 Electrofusion fitting
WO2016127103A2 (en) * 2015-02-06 2016-08-11 Mencos Ruben Adolfo Electrofusion pipe fittings, methods, and systems

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